The electrode for a secondary battery can be produced, for example, by preparing an active material, a conductive material, and a dispersed binder in a slurry paste state and then applying them on a current collector, followed by drying, rolling and further drying.
At this time, the binder in the electrode plays a role of ensuring flexibility of the electrode, and maintaining a sufficient binding force with the current collector.
On the other hand, one of the factors determining the flexibility of the electrode and the sufficient binding force with the current collector may include the content of the binder depending on the depth of the electrode. That is, the distribution of the binder in the electrode is an important factor in determining the flexibility of the secondary battery and the binding force with the current collector.
A drying process is required after applying a composition comprising a binder on a current collector to produce an electrode, but when the predetermined drying process is performed, a fine structure change is caused inside the electrode, whereby a problem that the performance of the electrode is deteriorated may be caused.
The above problem can be represented by a segregation phenomenon in which a binder existing in an electrode layer moves to a surface of the electrode during the drying process. Due to such a segregation phenomenon, there may be a problem that the binder is not evenly distributed inside the electrode, but biased to the surface.
Accordingly, various attempts are required to overcome the above-mentioned segregation phenomenon and binding force problems of the electrode capable of being caused therefrom.